Project Abstract Understanding the underlying causes of health disparities and developing effective methods to promote equitable health outcomes is a critical health policy goal. While we have substantial data showing large gaps in care between minority and non-minority patients, we have made little progress in eliminating these gaps. Previous studies indicate that optimal patient experiences with care may improve health outcomes and health status, and that minority patients report worse experiences with outpatient care than white patients. Yet, we have limited data on potential racial and ethnic disparities in patients' experiences in the hospital setting and factors that might explain these gaps. New national policy efforts, which aim to reward or penalize hospitals based on their performance on metrics of patient experience, create a need to understand whether hospitals that disproportionately care for minorities have worse performance and how we might intervene. Our work will examine both patient and hospital-level factors to better understand within and between hospital differences in patients' experiences and provide critically important data for interventions to promote equitable care. We propose to use patient-level data on patient experiences with hospital care from the HCAHPS database to examine four aims. We begin by examining whether there are racial or ethnic differences in care overall. We then examine the degree to which disparities in experience are due to within hospital differences, between hospital differences, or both. Our second aim will be to examine factors that explain or modify disparities within hospitals. Third, we will examine if the proportion of minority patients in a hospital is associated with hospital performance on patient experience metrics, and whether leadership's commitment to patient experience, financial health, and nurse staffing levels explain the relationship between proportion of minorities and patient experience. Finally, we will determine the role of these factors in improving patient experience over time. Our work will paint a national portrait of experiences of black, Hispanic, and white Americans in U.S. hospitals and provide timely data to ensure that national policies to improve care do not worsen disparities. We will quantify the degree to which disparities exist and whether they affect certain subgroups more than others. For example, if disparities in experience are most pronounced among the elderly or among hospitals with a large proportion of minority patients, these findings will provide targets for interventions. The analysis on institutional mediators should provide useful guidance about what interventions will most effectively reduce disparities in patient experience. Finally, our longitudinal analysis on how minority-serving hospitals improve over time will provide key insights about where to place future efforts to promote equitable, patient-centered care among all Americans.